On the eve of the launch of the newest commercial cargo vehicle to join the International Space Station’s resupply fleet, the Expedition 38 crew on board the orbiting complex supported a variety of scientific experiments Tuesday.

At a Launch Readiness Review, managers for Orbital Sciences Corporation and NASA gave a “go” to proceed toward the Wednesday launch of the Orbital-1 cargo resupply mission to the space station, pending the completion of remaining testing, data reviews and a Wallops Range Authority to Proceed. Orbital is targeting a 1:32 p.m. EST launch from Mid-Atlantic Regional Spaceport Pad-0A at NASA’s Wallops Flight Facility in eastern Virginia. NASA Television coverage of the launch will begin at 1 p.m.

There is a 95 percent chance of favorable weather at the time of launch. High, thick clouds are the primary concern for a weather violation. If needed, multiple back-up launch opportunities are available through Sunday.

When Cygnus arrives at the space station Sunday morning, Expedition 38 Flight Engineers Mike Hopkins and Koichi Wakata will capture the resupply vehicle with the station’s robotic arm and install it on the Earth-facing port of the station’s Harmony module.

Cygnus will deliver 2,780 pounds of supplies to the space station, including vital science experiments that will expand the research capabilities of the Expedition 38 crew members aboard the orbiting laboratory.

Aboard the station Tuesday, Flight Engineer Mike Hopkins began his workday setting up the Fluid Physics Experiment Facility for another round of science data collection.

Afterward, Hopkins spent much of his morning participating in the Body Measures study. With the assistance of Flight Engineer Koichi Wakata, Hopkins provided calibrated measurements of his body for researchers who are looking into the magnitude and variability of the human body during long-duration spaceflight. Predicting these changes will maximize crew performance, prevent injury and reduce time spent altering or adjusting spacesuits and workstations.

Meanwhile, Flight Engineer Rick Mastracchio tested a fluid sample from the Internal Thermal Control System (ITCS) within the Destiny laboratory and attached a wire tie to the sampling valve to prevent an inadvertent leak. Part of the station’s active thermal control system, the ITCS within the crew modules uses water for heating and cooling.

In the afternoon, Mastracchio worked with the Binary Colloidal Alloy Test-4 experiment, which studies how crystals form from solid materials suspended in a liquid. Results from this experiment will help researchers develop specialized crystals for high-speed computers, optical devices and other advanced materials. Mastracchio set up the sample module’s hardware and photographed ten slow growth samples.

Mastracchio and Hopkins took a break from their work to answers questions from students at Denbigh High School and Aviation Academy in Newport News, Va.

Wakata meanwhile performed ultrasound scans of his own legs for the Sprint investigation, which is an experiment that measures the effectiveness of high-intensity, low-volume exercise training in minimizing the loss of muscle mass and bone density that occurs during long-term exposure to weightlessness.

Afterward, Wakata donned sensors for a 36-hour data collection period of the Circadian Rhythms study. The knowledge gleaned from this experiment will not only provide important insights into the adaptations of the human autonomic nervous system in space over time, but also has significant practical implications by helping to improve physical exercise, rest- and work shifts as well as fostering adequate workplace illumination.

On the Russian side of the complex, Commander Oleg Kotov and Flight Engineer Mikhail Tyurin wiped down surfaces behind the panels inside the Zvezda service module and the Zarya module with a fungistat to inhibit the growth of fungi. Flight Engineer Sergey Ryazanskiy meanwhile cleaned ventilation screens inside Zvezda.